Project 3: The Neural Basis of Motion Guidance Loops Abstract The goal of Project 3 is to characterize the third level of four nested control loops, namely the Neural Basis of Motion Guidance. Motion guidance loops operate at the intersection of sensory and motor circuits to initiate and coordinate goal-directed behaviors. This project will dissect the circuits that control visually guided flight, that relay signals from motor centers into the visual periphery, and that underlie context-dependent switching of visual responses. To do this, the project will make use of genetic driver lines to target specific neuron types, as well as genetic effector molecules that alter neural activity and calcium dynamics. Functional outputs of the system will be measured using calcium and voltage imaging, as well as whole-cell electrophysiological recordings of neural activity, and behavior. Computational modeling will play central roles in both the design of visual stimuli, as well as in studies of network architecture and behavior. These efforts are divided into the following three Aims. Specific Aim 1: Determine the cellular basis of proportional-integral-derivative (PID) feedback in the flight motor system. Specific Aim 2: Determine how motor commands and hunger affect visual processing. Specific Aim 3: Investigate the mechanisms by which odor cues can switch the direction of visual orienting reflexes.